A known vehicle seat for a welfare vehicle is disclosed in JP 11-309175 A. This vehicle seat has a seat unit and a lift-up unit. The seat unit has a seat main body and foldable front and rear wheels. The lift-up unit is installed in the interior of a vehicle cabin and capable of moving the seat unit between the interior and the exterior of the vehicle cabin, with the seat main body kept in a seating posture. When the seat unit is moved into the vehicle cabin by means of this lift-up unit, the seat unit can be used as a vehicle cabin interior seat. Further, when the seat unit is moved to the exterior of the vehicle cabin by means of the lift-up unit, and then detached from the lift-up unit, the seat unit can be used as a wheelchair.
According to this vehicle seat, a seating person can get in and out of the vehicle while seating on the seat main body of the seat unit. Thus, the seating person need not get into the wheelchair from the vehicle seat or vice versa. As a result, burden on the seating person and a helper can be remarkably reduced. Further, the movement of the seat unit between the interior and the exterior of the vehicle cabin is performed by means of the lift-up unit. This may also remarkably reduce the burden on the helper.
Further, in this vehicle seat, the front and rear wheels of the seat unit can be folded along the lower surface of the seat main body. As a result, the height of the seat unit can be reduced when the seat unit is placed inside the vehicle cabin, thereby enabling the seating person to seat substantially at the same level as the other passengers inside the vehicle cabin.
However, this type of conventional vehicle seat is rather difficult to use for a driver's seat. Therefore, such a vehicle seat is restrictively applied to an assistant driver's seat and a rear seat (i.e., the seats other than the driver's seat). One of the reasons for this is that if this type of vehicle seat is applied to the driver's seat, the vehicle seat may interfere with the steering wheel when the seat unit moves between the interior and the exterior of the vehicle cabin.